Evaluation of Biostimulants Added to Post Emergence Herbicides in Soybean

Abstract

There is little information on the effect of the addition of biostimulants such as AX13-04-4, Crop Booster or RR Soy Booster to post emergence herbicides in soybean under Ontario environmental conditions. A total of 69 field experiments were conducted in soybean at two locations (Ridgetown and Exeter, Ontario, Canada) to evaluate the effect of biostimulants added to various post emergence herbicides on crop injury, weed control and yield of soybean. There was minimal soybean injury (6% or less) from glyphosate, chlorimuron, imazethapyr, fomesafen or quizalofop applied alone or in combination with biostimulants. At 4 weeks after herbicide treatment (WAT), the addition of biostimulants to glyphosate, chlorimuron, imazethapyr, fomesafen or quizalofop did not affect weed control except for control of common ragweed which was increased 2% with the addition of RR Soy Booster to glyphosate + imazethapr, and the control of common lambs quarters which was increased 4% with the addition of Crop Booster to glyphosate + fomesafen. At 8 WAT, biostimulants evaluated had no effect on weed control except for Crop Booster added to glyphosate + fomesafen which increased green foxtail control 2% and Crop Booster added to glyphosate + chlorimuron, glyphosate + fomesafen and glyphosate + quizalofop which increased common lambs quarters control 1%, 3%, and 4%, respectively. The addition of biostimulants to the post emergence herbicides evaluated had no effect on soybean yield. Based on these results, the addition of biostimulants such as AX13-04-4, Crop Booster or RR Soy Booster to commonly used post emergence herbicides in Ontario has no significant effect on crop injury, weed control or yield of soybean.